Change getRange to sublist. Make getRange deprecated.

sdk/lib/_internal/compiler/implementation/lib/js_array.dart

Index: sdk/lib/_internal/compiler/implementation/lib/js_array.dart
diff --git a/sdk/lib/_internal/compiler/implementation/lib/js_array.dart b/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
index b224b8324132542da0b2bcc474635f577aeda3bd..c86a14fc94d89d1ddf7a57a8cc43643e6abe8e5e 100644
--- a/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
+++ b/sdk/lib/_internal/compiler/implementation/lib/js_array.dart
@@ -146,23 +146,30 @@ class JSArray<E> implements List<E>, JSIndexable {
     return this[index];
   }
 
-  List<E> getRange(int start, int length) {
-    // TODO(ngeoffray): Parameterize the return value.
-    if (0 == length) return [];
+  List<E> sublist(int start, [int end]) {
     checkNull(start); // TODO(ahe): This is not specified but co19 tests it.
-    checkNull(length); // TODO(ahe): This is not specified but co19 tests it.
     if (start is !int) throw new ArgumentError(start);

[srdjan, 2013/03/18 16:24:41]

Isn't this different behavior than in the VM libraries? Didn't we agree not to
do explicit checks?

[floitsch, 2013/03/18 17:02:14]

If you want to have the same behavior on the VM and dart2js we have to check
types everywhere, as otherwise the code would need look the same on the two
platforms.
The result is used in a JS. We must check it. If you prefer we can move it
several lines down, but all 'start' checks are done here, so it makes sense to
do the type check here too.

-    if (length is !int) throw new ArgumentError(length);
-    if (length < 0) throw new ArgumentError(length);
-    if (start < 0) throw new RangeError.value(start);
-    int end = start + length;
-    if (end > this.length) {
-      throw new RangeError.value(length);
+    if (start < 0 || start > length) {
+      throw new RangeError.range(start, 0, length);
     }
-    if (length < 0) throw new ArgumentError(length);
+    if (end == null) {
+      end = length;
+    } else {
+      if (end is !int) throw new ArgumentError(end);
+      if (end < start || end > length) {
+        throw new RangeError.range(end, start, length);
+      }
+    }
+    // TODO(ngeoffray): Parameterize the return value.
+    if (start == end) return [];
     return JS('=List', r'#.slice(#, #)', this, start, end);
   }
 
+
+  List<E> getRange(int start, int length) {
+    return sublist(start, start + length);
+  }
+
   void insertRange(int start, int length, [E initialValue]) {
     checkGrowable(this, 'insertRange');
     if (length == 0) {